Pre-Emption Management in Sidelink Transmission Systems

Abstract

Methods to improve reselection of resources following pre-emption of reserved resources for sidelink communications. Reselection may be performed using an adjusted priority to reduce the prospects of the reselected transmission also being pre-empted. Alternatively the threshold used to decide whether resources have been pre-empted is adjusted if the resources are reselected rather than an initial selection.

1 . A method of scheduling sidelink transmissions between mobile stations in a cellular communications network, the method comprising the steps of
 at a first mobile station transmitting a first reservation with a first priority for first reserved transmission resources;   at the first mobile station detecting a second reservation by a second mobile station for second reserved transmission resources which overlap with the first reserved transmission resources;   at the first mobile station measuring the RSRP of the second reservation;   at the first mobile station comparing the measured RSRP to a first predefined threshold; and   if the measured RSRP is greater than the first predefined threshold, at the first mobile station considering the first reserved transmission resources as pre-empted, cancelling the transmission on the first reserved transmission resources, and initiating re-selection of transmission resources to replace the first reserved transmission resources using a second priority which is higher than the first priority.   
     
     
         2 . The method according to  claim 1 , wherein if the re-selected transmission resources are pre-empted, at the first mobile station performing a further re-selection with a priority that is higher than the second priority. 
     
     
         3 . The method according to  claim 1 , wherein the priority is increased by the same amount at each re-selection or by a different amount at each re-selection. 
     
     
         4 . (canceled) 
     
     
         5 . The method according to  claim 1 , further comprising at a third mobile station receiving a transmission on the re-selected transmission resources with an increased priority, and reducing that increased priority to the original value. 
     
     
         6 . The method according to  claim 1 , wherein the increase in priority is dependent on the mobile station's configuration or the resource pool of the transmission resources. 
     
     
         7 - 8 . (canceled) 
     
     
         9 . A method of scheduling sidelink transmissions between mobile stations in a cellular communications network, the method comprising the steps of
 at a first mobile station transmitting a first reservation with a first priority for first reserved transmission resources;   at the first mobile station detecting a second reservation by a second mobile station for second reserved transmission resources which overlap with the first reserved transmission resources;   at the first mobile station measuring the RSRP of the second reservation;   at the first mobile station comparing the measured RSRP for the second reservation to a threshold, wherein the threshold is dependent on whether the first reservation is a new reservation or a re-selection following pre-emption of a previous reservation; and   if the measured RSRP is greater than the threshold, at the first mobile station considering the first reserved transmission resources as pre-empted, cancelling the transmission on the first reserved transmission resources, and initiating re-selection of transmission resources to replace the first reserved transmission resources using the same priority as the first reservation.   
     
     
         10 . The method according to  claim 9 , wherein the threshold is dependent on the number of times the planned transmission has re-selected. 
     
     
         11 . The method according to  claim 9 , wherein the threshold is increased by the same amount for each previous re-selection or by a different amount at each re-selection. 
     
     
         12 - 13 . (canceled) 
     
     
         14 . The method according to  claim 9 , wherein the threshold is dependent on a configuration of the mobile station or a configuration of the resource pool of the reserved transmission resources. 
     
     
         15 . (canceled) 
     
     
         16 . A method of scheduling sidelink transmissions between mobile stations in a cellular communications network, the method comprising the steps of
 at a first mobile station transmitting a first reservation with a first priority for first reserved transmission resources;   at the first mobile station detecting a second reservation by a second mobile station for second reserved transmission resources which overlap with the first reserved transmission resources;   at the first mobile station measuring the RSRP for the second reservation;   at the first mobile station comparing the measured RSRP for the second reservation to a threshold, and   at the first mobile station transmitting on the first reserved transmission resources, wherein the transmission power is reduced dependent on the comparison of the measured RSRP to the threshold.   
     
     
         17 . The method according to  claim 16 , wherein the transmission power is reduced by the difference between the threshold and the measured RSRP or based on the difference between the threshold and the measured RSRP. 
     
     
         18 . (canceled) 
     
     
         19 . The method according to  claim 16 , wherein the reduction is dependent on a configuration of the mobile station or a configuration of the resource pool of the reserved transmission resources. 
     
     
         20 . (canceled) 
     
     
         21 . The method according to  claim 16 , wherein the threshold is dependent on whether the first reservation is a new reservation or a re-selection. 
     
     
         22 - 23 . (canceled) 
     
     
         24 . The method according to  claim 16 , wherein when the transmission power is reduced other transmission parameters are modified for transmissions on the first reserved transmission resources. 
     
     
         25 . The method according to  claim 24 , wherein the modulation coding scheme is adjusted, the code rate is increased, or a higher aggregation level is utilised. 
     
     
         26 . The method according to  claim 24 , wherein the modulation format of a second stage SCI transmitted in the first reserved transmission resources is adjusted when the transmission power is reduced. 
     
     
         27 . The method according to  claim 16 , wherein the position of reference symbols in the transmission on the first reserved transmission resources is adjusted to avoid a collision with reference symbols in the second reserved transmission resources. 
     
     
         28 . The method according to  claim 16 , wherein the position of a sidelink control information element in the transmission on the first reserved transmission resources is adjusted to avoid a collision with a sidelink control information element SCI in the second reserved transmission resources. 
     
     
         29 . The method according to  claim 16 , wherein if the difference between the measured RSRP and the threshold is greater than a second threshold, cancelling the first reservation and performing a re-selection. 
     
     
         30 . The method according to  claim 16 , wherein the transmission power on the first reserved transmission resources is increased if the priority of the second reservation is not higher than the first priority. 
     
     
         31 - 35 . (canceled)